Microstructures and mechanical properties of austempering Cr-Mo (SCM 435) alloy steel

Cheng Yi Chen, Fei-Yi Hung, Truan-Sheng Lui, Li Hui Chen

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

SCM435 is a Cr-Mo alloy steel and it is usually used to make the matrix of tempered-martensite by oil bath method, but it has some problems about reliability in the thin plate specimens. This research used the austempering heat treatment on the SCM435 thin plate specimen with a type of double loop and obtained the Cr-Mo bainite structure, and then we could further investigate the mechanical properties of SCM435 bainite materials. Experimental data showed that the stability of the mechanical properties of the specimen with austempering temperature 830°C for 25 min was better than that of 15 min. The size of the austenite grains affected the strength of thin plate bainite specimen. After austempering at 830°C for 25 min and salt bath at 290°C, the stability of the ultimate tensile strength (UTS) was better than that of the salt bath specimens at 310 and 330°C. The average hardness of all the specimens was more than HRA70. The specimen with austempering at 830°C for 25 min and salt bath at 290°C for 30 min had bigger grain size of the austenite and retained γ phase of 11.4 vol%. It also had higher hardness and strength. So, the austempering SCM435 alloy was improved for tensile strength comparing with traditional oil tempered-martensite process.

Original languageEnglish
Pages (from-to)56-60
Number of pages5
JournalMaterials Transactions
Volume54
Issue number1
DOIs
Publication statusPublished - 2013 Jan 7

Fingerprint

Bainite
Alloy steel
Salts
steels
mechanical properties
Martensite
salt baths
Austenite
Mechanical properties
microstructure
Microstructure
Oils
bainite
Tensile strength
Hardness
thin plates
baths
austenite
martensite
tensile strength

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

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abstract = "SCM435 is a Cr-Mo alloy steel and it is usually used to make the matrix of tempered-martensite by oil bath method, but it has some problems about reliability in the thin plate specimens. This research used the austempering heat treatment on the SCM435 thin plate specimen with a type of double loop and obtained the Cr-Mo bainite structure, and then we could further investigate the mechanical properties of SCM435 bainite materials. Experimental data showed that the stability of the mechanical properties of the specimen with austempering temperature 830°C for 25 min was better than that of 15 min. The size of the austenite grains affected the strength of thin plate bainite specimen. After austempering at 830°C for 25 min and salt bath at 290°C, the stability of the ultimate tensile strength (UTS) was better than that of the salt bath specimens at 310 and 330°C. The average hardness of all the specimens was more than HRA70. The specimen with austempering at 830°C for 25 min and salt bath at 290°C for 30 min had bigger grain size of the austenite and retained γ phase of 11.4 vol{\%}. It also had higher hardness and strength. So, the austempering SCM435 alloy was improved for tensile strength comparing with traditional oil tempered-martensite process.",
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Microstructures and mechanical properties of austempering Cr-Mo (SCM 435) alloy steel. / Chen, Cheng Yi; Hung, Fei-Yi; Lui, Truan-Sheng; Chen, Li Hui.

In: Materials Transactions, Vol. 54, No. 1, 07.01.2013, p. 56-60.

Research output: Contribution to journalArticle

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AB - SCM435 is a Cr-Mo alloy steel and it is usually used to make the matrix of tempered-martensite by oil bath method, but it has some problems about reliability in the thin plate specimens. This research used the austempering heat treatment on the SCM435 thin plate specimen with a type of double loop and obtained the Cr-Mo bainite structure, and then we could further investigate the mechanical properties of SCM435 bainite materials. Experimental data showed that the stability of the mechanical properties of the specimen with austempering temperature 830°C for 25 min was better than that of 15 min. The size of the austenite grains affected the strength of thin plate bainite specimen. After austempering at 830°C for 25 min and salt bath at 290°C, the stability of the ultimate tensile strength (UTS) was better than that of the salt bath specimens at 310 and 330°C. The average hardness of all the specimens was more than HRA70. The specimen with austempering at 830°C for 25 min and salt bath at 290°C for 30 min had bigger grain size of the austenite and retained γ phase of 11.4 vol%. It also had higher hardness and strength. So, the austempering SCM435 alloy was improved for tensile strength comparing with traditional oil tempered-martensite process.

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